<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<style type="text/css">
  .h,
  .f {
    width: 100%;
    height: 150px;
    background-color: pink;
    float: left;

  }

  .wrapper {
    padding: 0 200px;
  }

  .center {
    background-color: blue;
    width: 100%;
    height: 300px;

  }

  .left {
    background-color: brown;
    height: 300px;
    width: 200px;
    margin-left: -100%;
    position: relative;
    left: -200px;
  }

  .right {
    background-color: chartreuse;
    height: 300px;
    width: 200px;
    margin-left: -200px;
    position: relative;
    right: -200px;
  }

  .center,
  .left,
  .right {
    float: left;
  }
</style>

<body>
  <header class="h">头部</header>
  <div class="clearfix wrapper">
    <div class="center">主区域</div>
    <div class="left">左区域</div>
    <div class="right">右区域</div>
  </div>
  <footer class="f">底部</footer>

</body>

</html>